This study focuses on adult learners whose word reading grade equivalency levels range from 3.0 to 5.9. There are three components to this study. The first component evaluates the degree of explicitness that is necessary in teaching reading to low reading adults. Specifically, adults will be administered one of the following instructional approaches: decoding and fluency; reading comprehension and fluency; decoding, reading comprehension and fluency; extensive reading; decoding, reading comprehension, extensive reading, and fluency. Outcomes on reading measures of individuals in each of these groups will be compared to each other and to a control group of adult literacy learners who do not receive any of these approaches. All reading instructional approaches will be of equal length (100 hours), similar format, and independently monitored for integrity. For each of the five instructional groups, and the control group, 60 students will be evaluated (total n=360). Each sample will be randomly recruited from adult literacy students who enroll in existing adult literacy programs. Both repeated measures designs and learning growth curve modeling techniques will be used to evaluate treatment outcomes in relation to individual ability characteristics. The second component of this project is designed to evaluate differential outcomes based on subtype classifications. Data will be analyzed to identify subtypes of adult literacy learners, and whether these subtypes respond differentially to different instructional approaches. In other words, which instructional approach, or combination of instructional approaches is effective for the different subtypes of adult poor readers? The third and final component of this study includes fMRI technology. There are two aspects to this component. The first aspect is to provide a systematic evaluation of the different components of the neural circuitry of adult poor readers compared to adult expert readers. The second aspect is to evaluate whether fMRI may provide a neurobiological index of the impact of instruction on adult learners. In years 3 and 4 of our study, 10 adult expert readers and 10 adult poor readers will undergo fMRI studies of basic reading processes. In addition, we will scan 5 participants from each of our 6 groups before they receive instruction and after the 100th hour is completed.